It’s not tangential at all: they don’t hire me, they contract with a company that has relationships with a ton of “experts” and that company makes the connection, handles billing etc. they also have expert witnesses (often the same folks) etc. I have no idea how those guys find me. Word of mouth I presume.
I am really curious about the company that you work through. Place I contract with right now really could use some of that expert advice(not software engineering issue)